An Experimental Study of the Load-Orientation Sensitivity of Three-Lobe Bearings

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Rasish Khatri ◽  
Dara W. Childs
Keyword(s):  
Performance Test ◽  
Static Load ◽  
Dynamic Performance ◽  
Dynamic Test ◽  
Load Condition ◽  
Leading Edge ◽  
Test Results ◽  
Static Data ◽  
Load Vector ◽  
All Speeds

Static and dynamic performance test results are provided for a three-lobe bearing evaluated over the following range of radial static-load orientations (taken from the leading edge of the loaded pad): 0 deg, 20 deg, 30 deg, 40 deg, 60 deg, 80 deg, 90 deg, and 100 deg. Static and dynamic test results are evaluated to determine the sensitivity of the bearing to changes in the static load direction. The bearing has the following specifications: 100 deg arc angle, 0.52 preload, 70% offset, 101.74 mm minimum bore diameter, 0.116 mm radial pad clearance, and 76.3 mm axial length. The bearing is tested at 6750 rpm, 9000 rpm, 10,800 rpm, and 13,200 rpm, and at five different unit loads. Static measurements include hot and cold clearances, static eccentricities, and pad metal temperatures. Dynamic results include stiffness coefficients, damping coefficients, and whirl-frequency ratios (WFRs). Dynamic tests show that the three-lobe bearing is very sensitive to load orientation at low speeds and high loads. Kxx is highest for the 80 deg, 90 deg, and 100 deg load orientations. Kyy is highest for the 20 deg, 30 deg, and 40 deg load orientations. Kxy is highest for the 80 deg, 90 deg, and 100 deg load orientations. The magnitude of Kyx is highest for the 0 deg and 20 deg load orientations. Cxx is largest for the 80 deg, 90 deg, and 100 deg load orientations, and Cyy is largest for the 0 deg, 20 deg, 30 deg, and 40 deg load orientations. In terms of WFRs, it is generally dynamically advantageous to orient the static load vector for this bearing toward the leading edge of the pad. WFRs at 6750 rpm with loads of 1149 kPa, 1723 kPa, and 2298 kPa are equal to zero when the static load vector is pointed toward the leading edge of the pad and between 0.25 and 0.5 when the static load vector is pointed toward the trailing edge of the pad. The bearing is not sensitive to load orientation at high speeds and light loads. At 13,200 rpm, measured WFRs are between 0.2 and 0.6 at all loads and for all load orientations. Measured WFRs at the no-load condition are between 0.3 and 0.6 at all speeds. Static data showed that the 30 deg and 90 deg load orientations yielded slightly higher measured maximum pad-metal-temperature increases at each speed relative to the other load orientations. At the highest static-load magnitudes, the pad metal temperatures are not as dependent on load orientation. The 20 deg, 30 deg, and 40 deg load orientations had the smallest measured eccentricity ratio, and thus the highest static stiffness.

An Experimental Study of the Load-Orientation Sensitivity of Three-Lobe Bearings

2014 ◽  
Author(s):  
Rasish Khatri ◽  
Dara W. Childs
Keyword(s):  
Performance Test ◽  
Static Load ◽  
Dynamic Performance ◽  
Dynamic Test ◽  
Load Condition ◽  
Leading Edge ◽  
Test Results ◽  
Static Data ◽  
Load Vector ◽  
All Speeds

Static and dynamic performance test results are provided for a three-lobe bearing evaluated over the following range of radial static-load orientations (taken from the leading edge of the loaded pad): 0°, 20°, 30°, 40°, 80°, 90°, and 100°. Static and dynamic test results are evaluated to determine the sensitivity of the bearing to changes in the static load direction. The bearing has the following specifications: 100o arc angle, 0.52 preload, 70% offset, 101.74 mm minimum bore diameter, 0.116 mm radial pad clearance, and 76.3 mm axial length. The bearing is tested at 6750 rpm, 9000 rpm, 10800 rpm, and 13200 rpm, and at five different unit loads. Static measurements include hot and cold clearances, static eccentricities, and pad metal temperatures. Dynamic results include stiffness coefficients, damping coefficients, and whirl-frequency ratios (WFRs). Dynamic tests show that the three-lobe bearing is very sensitive to load orientation at low speeds and high loads. Kxx is highest for the 80°, 90°, and 100° load orientations. Kyy is highest for the 20°, 30°, and 40° load orientations. Kxy is highest for the 80°, 90°, and 100° load orientations. The magnitude of Kyx is highest for the 0° and 20° load orientations. Cxx is largest for the 80°, 90°, and 100° load orientations, and Cyy is largest for the 0°, 20°, 30°, and 40° load orientations. In terms of WFRs, it is generally dynamically advantageous to orient the static load vector for this bearing towards the leading edge of the pad. WFRs at 6750 rpm with loads of 1149 kPa, 1723 kPa, and 2298 kPa are equal to zero when the static load vector is pointed towards the leading edge of the pad and between 0.25 and 0.5 when the static load vector points towards the trailing edge of the pad. The bearing is not sensitive to load orientation at high speeds and light loads. At 13200 rpm, measured WFRs are between 0.2 and 0.6 at all loads and for all load orientations. Measured WFRs at the no-load condition are approximately 0.5 at all speeds. Static data showed that the 30° and 90° load orientations yielded slightly higher measured maximum pad-metal-temperature increases at each speed relative to the other load orientations. At the highest static-load magnitudes, the pad metal temperatures are not as dependent on load orientation. The 20°, 30°, and 40° load orientations had the smallest measured eccentricity ratio, and thus the highest static stiffness.

An Experimental Investigation of the Dynamic Performance of a Vertical-Application Three-Lobe Bearing

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Rasish Khatri ◽  
Dara W. Childs
Keyword(s):  
Performance Test ◽  
Dynamic Performance ◽  
Load Condition ◽  
Leading Edge ◽  
Test Results ◽  
Damping Coefficients ◽  
Stiffness Coefficients ◽  
Numerical Predictions ◽  
Frequency Independent ◽  
Direct Stiffness

Dynamic performance test results are provided for a vertical-application three-lobe bearing, geometrically similar to a three-lobe bearing tested by Leader et al. (2010, “Evaluating and Correcting Subsynchronous Vibration in Vertical Pumps,” 26th International Pump Users Symposium, Houston, TX, March 16-18) to stabilize a vertical sulfur pump. The bearing has the following specifications: 100 deg pad arc angle, 0.64 preload, 100% offset, 101.74 mm bore diameter, 0.116 mm radial pad clearance, 76.3 mm axial length, and 100 deg static load orientation from the leading edge of the loaded pad. The bearing is tested at 2000 rpm, 4400 rpm, 6750 rpm, and 9000 rpm. This bearing is tested in the no-load condition and with low unit loads of 58 kPa and 117 kPa. The dynamic performance of this bearing is evaluated to determine (1) whether a fully (100%) offset three-lobe bearing configuration is more stable than a standard plain journal bearing (0.5 whirl-frequency ratio (WFR)) and (2) whether a fully offset three-lobe bearing provides a larger direct stiffness than a standard fixed-arc bearing. Hot and cold clearances are measured for this bearing. Dynamic measurements include frequency-independent stiffness and damping coefficients. Bearing stability characteristics are evaluated using the WFR. Test results are compared to numerical predictions obtained from a fixed-arc bearing Reynolds equation solver. Dynamic tests show that the vertical-application three-lobe bearing does not improve stability over conventional fixed-arc bearings. The measured WFRs for the vertical-application bearing are approximately 0.4–0.5 for nearly all test cases. Predicted WFRs are 0.46 at all test points. The vertical-application bearing dimensionless direct stiffness coefficients were compared to those for a 70% offset three-lobe bearing. Dimensionless direct stiffness coefficients at 0 kPa are larger for the vertical-application bearing by 45–48% in the loaded direction and larger by 15–26% in the unloaded direction. Thus, the vertical-application bearing does impart a larger centering force to the journal relative to the 70% offset bearing, in the no-load condition. Predictions using both the measured hot clearance and measured cold clearance as inputs to the code are compared to the measured dynamic data. In general, the predicted direct stiffness coefficients using both the hot and cold clearances as inputs were higher than measured direct stiffnesses. The two sets of predicted cross-coupled stiffness coefficients straddle the measured cross-coupled stiffness coefficients. Predicted direct damping coefficients using both solutions were higher than measured values in most cases, but agreement between predictions and measurements improved significantly at high speeds and when applying light loads.

An Experimental Investigation of the Dynamic Performance of a Vertical-Application Three-Lobe Bearing

2014 ◽  
Author(s):  
Rasish Khatri ◽  
Dara W. Childs
Keyword(s):  
Frequency Ratio ◽  
Performance Test ◽  
Dynamic Performance ◽  
Load Condition ◽  
Leading Edge ◽  
Test Results ◽  
Damping Coefficients ◽  
Stiffness Coefficients ◽  
Numerical Predictions ◽  
Direct Stiffness

Dynamic performance test results are provided for a vertical-application three-lobe bearing, geometrically similar to a three-lobe bearing tested by Leader [1] to stabilize a vertical sulfur pump. The bearing has the following specifications: 100° pad arc angle, 0.64 preload, 100% offset, 101.74 mm bore diameter, 0.116 mm radial pad clearance, 76.3 mm axial length, and 100° static load orientation from the leading edge of the loaded pad. The bearing is tested at 2000 rpm, 4400 rpm, 6750 rpm, and 9000 rpm. This bearing is tested in the no-load condition and with low unit loads of 58 kPa and 117 kPa. The dynamic performance of this bearing is evaluated to determine (1) whether a fully (100%) offset three-lobe bearing configuration is more stable than a standard plain journal bearing (0.5 whirl-frequency ratio), and (2) whether a fully offset three-lobe bearing provides a larger direct stiffness than a standard fixed-arc bearing. Hot and cold clearances are measured for this bearing. Dynamic measurements include frequency-independent stiffness and damping coefficients. Bearing stability characteristics are evaluated using the whirl-frequency ratio (WFR). Test results are compared to numerical predictions obtained from a fixed-arc bearing Reynolds equation solver. Dynamic tests show that the vertical-application three-lobe bearing does not improve stability over conventional fixed-arc bearings. The measured WFRs for the vertical-application bearing are approximately 0.4–0.5 for nearly all test cases. Predicted WFRs are 0.46 at all test points. The vertical-application bearing dimensionless direct stiffness coefficients were compared to those for a 70% offset three-lobe bearing. Dimensionless direct stiffness coefficients at 0 kPa are larger for the vertical-application bearing by 45–48% in the loaded direction and larger by 15–26% in the unloaded direction. Thus, the vertical-application bearing does impart a larger centering force to the journal relative to the 70% offset bearing, in the no-load condition. Predictions using both the measured hot clearance and measured cold clearance as inputs to the code are compared to the measured dynamic data. In general, the predicted direct stiffness coefficients using both the hot and cold clearances as inputs were higher than measured direct stiffnesses. The two sets of predicted cross-coupled stiffness coefficients straddle the measured cross-coupled stiffness coefficients. Predicted direct damping coefficients using both solutions were higher than measured values in most cases, but agreement between predictions and measurements improved significantly at high speeds and when applying light loads.

Hydraulic Fluidics

1973 ◽  
Vol 95 (2) ◽  
pp. 161-166
Author(s):  
L. R. Kelley ◽  
W. A. Boothe
Keyword(s):  
Reynolds Number ◽  
Performance Test ◽  
Dynamic Performance ◽  
Effective Means ◽  
Parameter Analysis ◽  
Test Results ◽  
High Dependency ◽  
Lumped Parameter ◽  
Fluidic Devices ◽  
Hydraulic Operation

Fluidic technology is equally applicable to liquid and gaseous operation, yet the bulk of the literature to date is concerned with the latter. This paper describes some of the unique effects encountered in fluidic devices for hydraulic operation, and compares air operation to hydraulic oil operation in several critical respects including potential response, power consumption, and Reynolds number. Test data on oil operated hydraulic elements show a high dependency on Reynolds number in the lower pressure and temperature regions. Gain as a function of Reynolds number and aspect ratio is presented. An effective means for correlating data to a modified Reynolds number is shown. Dynamic performance test results are also shown, and agree quite well with predictions based on lumped parameter analysis. The use of operational oil elements in specific open and closed-loop circuits is also described.

scholarly journals COMPARISON OF BIODIESEL B-20 AND B-30 ON DIESEL ENGINE PERFORMANCES AND EMISSIONS

2018 ◽  
Vol 39 (3) ◽  
Author(s):  
Lies Aisyah ◽  
Cahyo Setyo Wibowo ◽  
Sylvia Ayu Bethari
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Performance Test ◽  
Cetane Number ◽  
Load Condition ◽  
Esterification Reaction ◽  
Test Results ◽  
Engine Torque ◽  
Smoke Opacity ◽  
Engine Power

Biodiesel is renewable energy that is made from renewable sources such as vegetable oil (palm oil, soybean oil or jathropa oil) through a trans-esterification reaction. Biodiesel can be used as a substitute for diesel fuel or as a mixture with diesel fuel. B-20 and B-30 fuel are a biodiesel mixture with diesel fuel which contains 20% biodiesel and 80% diesel fuel and 30% biodiesel and 70% diesel fuel respectively. The aim of this study is to compare the performance tests of B-20 and B-30 on a diesel engine. Comparison of their performance comprises engine power, engine torque, specific fuel consumption (SFC) in various loads and emissions. Result shows that the B-20 and B-30 performance is affected by the chemical-physical characteristics of fuel, such as kinematic viscosity, cetane number, density and calorific values. Performance test results show that B-30 has 1.69% lower engine power and 0.62% higher SFC than B-20 at a full load condition. In contrast, B-30 has better emissions than B-20 with a 6.71% decrease in smoke opacity.

Validation of SST 300 bearing casing for SST 200 bearing casing in static load condition

2011 ◽  
Vol 3 (7) ◽  
pp. 277-278
Author(s):  
Jinesh Shah ◽  
◽  
Mohammad Azim Aijaz ◽  
Pratik Kikani ◽  
Sagarkumar Shah ◽  
...  
Keyword(s):  
Static Load ◽  
Load Condition

In-Plane Flexible Ring Tire Model—Part 1: Modeling and Parameter Identification

2018 ◽  
Vol 46 (3) ◽  
pp. 174-219 ◽  
Author(s):  
Bin Li ◽  
Xiaobo Yang ◽  
James Yang ◽  
Yunqing Zhang ◽  
Zeyu Ma
Keyword(s):  
Static Load ◽  
Model Parameters ◽  
Tire Model ◽  
Test Results ◽  
Lumped Mass ◽  
Virtual Test ◽  
Proposed Model ◽  
Particle Swarm Method ◽  
Vehicle Dynamic Simulation ◽  
Flexible Ring

ABSTRACT The tire model is essential for accurate and efficient vehicle dynamic simulation. In this article, an in-plane flexible ring tire model is proposed, in which the tire is composed of a rigid rim, a number of discretized lumped mass belt points, and numerous massless tread blocks attached on the belt. One set of tire model parameters is identified by approaching the predicted results with ADAMS® FTire virtual test results for one particular cleat test through the particle swarm method using MATLAB®. Based on the identified parameters, the tire model is further validated by comparing the predicted results with FTire for the static load-deflection tests and other cleat tests. Finally, several important aspects regarding the proposed model are discussed.

PENGARUH MODEL PEMBELAJARAN KELILING KELOMPOK (ROUND CLUB) TERHADAP KETERAMPILAN MENULIS LAPORAN PERJALANAN SISWA KELAS V SDN 01 NAGARI BUKIK SIKUMPA

2020 ◽  
Author(s):  
Wirda Linda
Keyword(s):  
Standard Deviation ◽  
Performance Test ◽  
Writing Skills ◽  
Learning Model ◽  
Homogeneity Test ◽  
Test Results ◽  
Class V ◽  
Average Value ◽  
Normality Test ◽  
Lecture Method

This research is motivated by the low desire of students in writing travel reports. The lack of students' knowledge of the report concept, the lack of students' knowledge of the 5W + 1H report points of good and correct language, the lack of students' knowledge of the spatial, time and topic pattern and not yet reached KKM 75. The method used by the teacher has not been interesting, lecture method. The purpose of this study is to describe the skills of writing travel reports by using Round Club learning model which is viewed from the aspect of understanding the report concept, the use of 5W +1H report points, the spatial, time, and topic pattern.The population of this study is the students of class V Lessons Year 2017/2018 which amounted to 2 classes with the number 80. The sample of research as much as two classes taken by the sample of propotional.Class V.1 as experimental class and class V.2 as control class. The research instrument used is performance test. Provide an assessment by specifying the subject of the 5W + 1H report, as well as the spatial, time and topic pattern. Data were analyzed by 't' test by first testing normality, homogeneity, and hypothesis testing.The results showed that the average control class 68 with more than enough qualifications with standard deviation 16.96. 83 experimental class with good qualification and standard deviation of 15.42 and there is a significant influence on the result of writing skill of class V SDN 01 Nagari Bukik SikumpaSubdistrict, Lima Puluh Kota. This is evidenced by the average value of writing skills in the experiment class higher than the average value in the control class. Normality test results indicate that the two sample classes of  Lo  values in the control class -0.2141 are smaller than the normal 0.190 Lt distributed. Homogeneity test results that the variation of this study is homogeneous at a real level of 0.05, because Ftable 2.16 > Fhitung 1.21 and the results of data analysis then obtained = 2.78 > 1.70 t table, so H0 rejected and H1 accepted. It can be concluded that there is Influence. Using  Learning  Model of Student Group Writing  Skills Travel Report of students of class V SDN 01 Nagari Bukik Sikumpa Subdistrict, Kabupaten Lima Puluh Kota.KeyWords: model pembelajaran round club, menulis laporan perjalanan.

Research on Static Load Tests of Damaged Bridge Strengthened with Pre-Stressed HFRP

2014 ◽  
Vol 1079-1080 ◽  
pp. 258-265
Author(s):  
Chen Ning Cai ◽  
Shan He ◽  
Li Na Liu ◽  
Shi Kun Ou
Keyword(s):  
Static Load ◽  
Flexural Rigidity ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Structural Members ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Load Tests

Thispaper presents an experimental study to strengthen an existing bridge usingpre-stressed carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer(GFRP) materials. The method using pre-stressed hybrid fiber reinforced polymer(HFRP) to strengthened structural members is an emerging pre-stressed strengtheningtechnology. In this study, experimental data selected from result of staticloading test conducted to hollow slabs with CFRP/GFRP has been compared with specimenswithout strengthening. Test results showed that the strengthening methoddeveloped in this study could effectively reduce the stress in hollow slab,improving the flexural rigidity and inhibiting the concrete from fracture.

Sign in / Sign up

Export Citation Format

Share Document